1. Technical Field
The present disclosure relates generally to microwave systems and devices. More particularly, the present disclosure relates systems and devices for microwave and millimeter-wave signal transmission, amplification and energy delivery to tissue.
2. Background of Related Art
In the treatment of diseases such as cancer, certain types of cancer cells have been found to denature at elevated temperatures (which are slightly lower than temperatures normally injurious to healthy cells). These types of treatments, known generally as hyperthermia therapy, typically utilize electromagnetic radiation to heat diseased cells to temperatures above 41° C. while maintaining adjacent healthy cells at lower temperatures to insure that irreversible cell destruction does not occur. Other procedures utilizing electromagnetic radiation to heat tissue also include ablation and coagulation of the tissue. Such procedures, e.g., such as those performed for menorrhagia, are typically performed to ablate and coagulate the targeted tissue to denature or kill the tissue. Many procedures and types of devices utilizing electromagnetic radiation therapy are known in the art and are typically used in the treatment of tissue and organs such as the prostate, heart, and liver.
Electronic heating of tissue may be accomplished by at least two methods. A first method of electronic heating utilizes the production or induction of an electric current in tissue. An electric current may be produced between two electrodes, between an electrode and a return pad or the current may be induced by an oscillating electric field. As such, heating with an electric current requires the tissue to be conductive or at least partially conductive.
A second method of electronic heating, which utilizes dipolar rotation wherein heat is generated by the movement of molecules by an electric field, is known as dielectric heating. Dielectric heating requires the use of energy in or around a microwave frequency and generates heat in both conductive and nonconductive tissues.
The basic components of the microwave energy delivery system are similar to the components that comprise a conventional microwave ablation system and included a power source and impendence matching circuit to generate microwave energy and an electrode means for delivering the microwave energy to tissue. The microwave generator circuit connects to the electrode by any known suitable connection. Present microwave energy delivery systems include a microwave generator that connects to a microwave energy delivery device, i.e., a tissue penetrating or catheter device, via a semi-rigid coaxial cable.
While many advances have been made in the field of electrosurgical microwave ablation, a conventional electrosurgical microwave system still includes separate components for microwave signal generation, microwave signal transmission and microwave energy delivery (i.e., a generator, coaxial cable and delivery device).